Insulating guard



Oct. 5,1946. 5. R. HERMANN 2 409,042

INSULATING GUARD Filed Dec. 5, 1942 Ihventor: Ber j amin R. Hermann,

His Attorney- Patented Oct. 8, 1946 UNITED STATES PATENT OFFICE INSULATING GUARD Benjamin B. Hermann, Lanesborough, Mass.,

assignor to General Electric Company, a corporation of New York Application December 5, 1942, Serial No. 467,974

5 Claims. 1

My invention relates to an insulating guard for insulating the exposed conducting portions of a circuit interrupting device and is in the nature of an improvement on my prior Patent 2,163,398 assigned to the same assignee as the present application.

Service outages frequently result from faults which have been initiated by foreign objects establishing a low resistance path from conducting parts of an electrical apparatus to ground. To cite a specific example, in the case of dis-- tribution transformer installations which have fuse cutouts or similar circuit interrupting devices mounted on the bushings thereof as is disclosed in my prior patent referred to above, it has been observed that birds are prone to alight on the transformer covers and attracted by the bright metal conducting parts, peek at them and thus initiate an arc-over. For preventing service interruptions from causes such as these, it is desirable to provide a simple means for covering or guarding the exposedconducting portions of electrical apparatus to prevent foreign objects from adversely affecting such apparatus.

It is therefore an object of my invention to provide a simple, inexpensive insulating guard which is firmly held in position to protect exposed conducting portions of electrical apparatus.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a view of the upper ortion of an electrical apparatus embodying my invention and Fig. 2 is an enlarged perspective view partly in section of the insulating guard of my invention illustrated in Fig. 1.

Although for the purpose of illustrating my invention in the drawing, it has been shown as adapted for application to the high voltage bushing of a transformer and the supporting mechanism for a fuse cutout, it will be obvious that the invention is not to be necessarily so limited. It will become apparent as the decription proceeds that the insulating guard of the present invention may be applicable for the protection of exposed conducting parts of electrical apparatus generally.

Referring now to Fig. 1 the transformer I0 is illustrated as being provided with a cover I I upon which is mounted a high voltage bushing I2 having a terminal I3 at the upper end thereof, clearly shown in Fig. 2 of the drawing. A suitable circuit interrupting device I4 which may be similar to the circuit interrupting device illustrated in my prior Patent 2,163,398 referred to above, is mechanically supported from terminal I3 by means of a support generally indicated at I5 which comprises an L-shaped member I5 suitably welded to a U-shaped member I 5". The U-shaped member I5 is adapted to embrace the housing of the circuit interrupting device I4 which is provided with a suitable conducting stud such as is indicated in my prior patent referred to above which cooperates with the opening I6 in support I5 to rigidly fasten circuit interrupting device I4 to terminal I3. As is disclosed in my prior patent circuit interrupting device I4 is preferably a fuse cutout having one terminal thereof electrically connected with the supporting stud which cooperates with opening I B in support I5 so that support I5 electrically interconnects terminal I3 and circuit interrupting device I4. Support I5 is suitably fastened to terminal I3 as by means of a bolt 11.

In order to prevent a foreign object such as a bird from standing on the cover II of transformer I0 and pecking at support I5 or terminal I3 to initiate a bushing arc-over, I provide an insulating guard which comprises two separate insulating members I8 and I9. Insulating member I8 is adapted to completely enclose a portion of the exposed parts of U-shaped member I5" and is in theshape of a tube somewhat rectangular in cross section with a notched-out or recessed portion I8 so as to closely fit around the housing of the circuit interrupting device l4. Insulating member I8 is slipped over support I5 after support I5 is suitably fastened to circuit interrupting device I4 but before arm or support I5 is fastened to terminal I3 as by bolt I I. Preferably insulating member I 8 is made of suitable ceramic material such as porcelain or the like.

Insulating member I9 is preferably constructed of the same material as insulating member I8 and is somewhat cup-shaped with an open bottom and one open side 20 which cooperatively engages with the opening in the adjacent end of tubular insulating member I8. Adjacent one edge of opening 20 is a suitable abutment 2| having a wedge shaped end 22 adjacent the lower opening of insulating member I9. After the circuit interrupting device I4 is suitably mounted on terminal I3 by virtue of support I5, and insulating member I8 is in place, insulating member or cap I9 is slipped over terminal I3 and the exposed portion of support |5 to completely enclose the conducting parts electrically interconnecting transformer Ill and circuit interrupting device M.

In order to prevent the wind or any other means from blowing or moving cap l9 out of position, which in turn would permit insulating mem ber Hi to move out of position, I provide a latching or retaining means 23 which comprises a spring member of L-shaped construction having one end thereof welded to member l5 as indicated at 24. The other end of latching means 23 extends through an opening 25 in member l5 so as to engage the abutment 2| in the manner indicated in Fig. 2 with suflicient pressure, not only to prevent cap I 9 from slipping away from insulating member la in a generally horizontal direction, but also from being accidentally moved away from terminal l3 in a generally vertical direction as by the Wind or the like. With this arrangement a lineman can readily remove insulating cap I9 by liftin it upwardly to expose terminal l3. The wedge shaped portion 22 of abutment 2| permits the ready application of insulating cap l9 so as to permit spring member 23 to frictionally engage abutment 2| without requiring additional means to deflect spring means 23 so that cap I9 may be moved into position. It will be observed that the insulating guard described not only completely encloses the exposed parts of the support l5 and terminal |3, but is very simple to apply, and in addition provides a very pleasing appearance, The latching means described assures that the insulating guard remains in position against the action of the wind, etc.

Having described my invention in what I consider to be a preferred embodiment thereof, I desire to have it understood that the specific form shown is merely illustrative and that I intend in the following claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination with an electrical device, an insulator including an electrical terminal at one end thereof, a circuit interrupting device, a supporting arm for said circuit interrupting device mounted on said terminal and electrically interconnecting said circuit interrupting device and said terminal, a resilient member mounted on said arm, a guard of insulating material enclosing the exposed parts of said terminal and arm for preventing foreign objects from adversely aifecting said circuit interrupting device, and means including said resilient member engaging said guard to hold said guard in position on said arm.

2. In combination with an electrically conducting supporting arm having exposed portions, a guard for preventing foreign objects from coming in contact with the exposed portions of said arm comprising a first insulating member for completely enclosing a portion of said arm, a second insulating member for enclosing the remaining exposed portions of said arm, and a spring member supported by said arm frictionall engaging a portion of said second member for holding said second insulating member in position, said first insulating member being held in position by said second insulating member.

3. In combination with an electrically conducting supporting arm having exposed portions, a cap for enclosing an exposed portion of said arm, said cap including an abutment, a spring member supported by said arm and arranged frictionally to engage said abutment to hold said cap on said and means including a Wedgeshaped portion on said abutment to enable said cap to be readily positioned on said arm without interference from said spring member.

In combination with an electrical device, an insulating bushing including an electrical terminal at one end thereof, a circuit interrupting device, a supporting arm for said circuit interrupting device mounted on said terminal and electrically interconnecting said circuit interrupting device and said terminal, and a guard of insulating material comprising a first portion for said supporting arm and a second portion for said terminal, said first portion being held in position by said second portion.

5. In combination with an electrical device, an insulating bushing including an electrical terminal at one end thereof, a circuit interrupting device, a supporting arm for said circuit interrupting device mounted on said terminal and electrically interconnecting said circuit interrupting device and said terminal, guard means of insulating material for preventing foreign objects from coming in contact with the exposed portions of said arm, said guard means being so constructed and arranged that said arm is at least partially encircled, and means including one of said p01- tions of said arm for holding said guard means in position thereon.

BENJAMIN R. HERMANN. 

